1=pod 2 3=head1 NAME 4 5DES_random_key, DES_set_key, DES_key_sched, DES_set_key_checked, 6DES_set_key_unchecked, DES_set_odd_parity, DES_is_weak_key, 7DES_ecb_encrypt, DES_ecb2_encrypt, DES_ecb3_encrypt, DES_ncbc_encrypt, 8DES_cfb_encrypt, DES_ofb_encrypt, DES_pcbc_encrypt, DES_cfb64_encrypt, 9DES_ofb64_encrypt, DES_xcbc_encrypt, DES_ede2_cbc_encrypt, 10DES_ede2_cfb64_encrypt, DES_ede2_ofb64_encrypt, DES_ede3_cbc_encrypt, 11DES_ede3_cbcm_encrypt, DES_ede3_cfb64_encrypt, DES_ede3_ofb64_encrypt, 12DES_cbc_cksum, DES_quad_cksum, DES_string_to_key, DES_string_to_2keys, 13DES_fcrypt, DES_crypt, DES_enc_read, DES_enc_write - DES encryption 14 15=head1 SYNOPSIS 16 17 #include <openssl/des.h> 18 19 void DES_random_key(DES_cblock *ret); 20 21 int DES_set_key(const_DES_cblock *key, DES_key_schedule *schedule); 22 int DES_key_sched(const_DES_cblock *key, DES_key_schedule *schedule); 23 int DES_set_key_checked(const_DES_cblock *key, 24 DES_key_schedule *schedule); 25 void DES_set_key_unchecked(const_DES_cblock *key, 26 DES_key_schedule *schedule); 27 28 void DES_set_odd_parity(DES_cblock *key); 29 int DES_is_weak_key(const_DES_cblock *key); 30 31 void DES_ecb_encrypt(const_DES_cblock *input, DES_cblock *output, 32 DES_key_schedule *ks, int enc); 33 void DES_ecb2_encrypt(const_DES_cblock *input, DES_cblock *output, 34 DES_key_schedule *ks1, DES_key_schedule *ks2, int enc); 35 void DES_ecb3_encrypt(const_DES_cblock *input, DES_cblock *output, 36 DES_key_schedule *ks1, DES_key_schedule *ks2, 37 DES_key_schedule *ks3, int enc); 38 39 void DES_ncbc_encrypt(const unsigned char *input, unsigned char *output, 40 long length, DES_key_schedule *schedule, DES_cblock *ivec, 41 int enc); 42 void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, 43 int numbits, long length, DES_key_schedule *schedule, 44 DES_cblock *ivec, int enc); 45 void DES_ofb_encrypt(const unsigned char *in, unsigned char *out, 46 int numbits, long length, DES_key_schedule *schedule, 47 DES_cblock *ivec); 48 void DES_pcbc_encrypt(const unsigned char *input, unsigned char *output, 49 long length, DES_key_schedule *schedule, DES_cblock *ivec, 50 int enc); 51 void DES_cfb64_encrypt(const unsigned char *in, unsigned char *out, 52 long length, DES_key_schedule *schedule, DES_cblock *ivec, 53 int *num, int enc); 54 void DES_ofb64_encrypt(const unsigned char *in, unsigned char *out, 55 long length, DES_key_schedule *schedule, DES_cblock *ivec, 56 int *num); 57 58 void DES_xcbc_encrypt(const unsigned char *input, unsigned char *output, 59 long length, DES_key_schedule *schedule, DES_cblock *ivec, 60 const_DES_cblock *inw, const_DES_cblock *outw, int enc); 61 62 void DES_ede2_cbc_encrypt(const unsigned char *input, 63 unsigned char *output, long length, DES_key_schedule *ks1, 64 DES_key_schedule *ks2, DES_cblock *ivec, int enc); 65 void DES_ede2_cfb64_encrypt(const unsigned char *in, 66 unsigned char *out, long length, DES_key_schedule *ks1, 67 DES_key_schedule *ks2, DES_cblock *ivec, int *num, int enc); 68 void DES_ede2_ofb64_encrypt(const unsigned char *in, 69 unsigned char *out, long length, DES_key_schedule *ks1, 70 DES_key_schedule *ks2, DES_cblock *ivec, int *num); 71 72 void DES_ede3_cbc_encrypt(const unsigned char *input, 73 unsigned char *output, long length, DES_key_schedule *ks1, 74 DES_key_schedule *ks2, DES_key_schedule *ks3, DES_cblock *ivec, 75 int enc); 76 void DES_ede3_cbcm_encrypt(const unsigned char *in, unsigned char *out, 77 long length, DES_key_schedule *ks1, DES_key_schedule *ks2, 78 DES_key_schedule *ks3, DES_cblock *ivec1, DES_cblock *ivec2, 79 int enc); 80 void DES_ede3_cfb64_encrypt(const unsigned char *in, unsigned char *out, 81 long length, DES_key_schedule *ks1, DES_key_schedule *ks2, 82 DES_key_schedule *ks3, DES_cblock *ivec, int *num, int enc); 83 void DES_ede3_ofb64_encrypt(const unsigned char *in, unsigned char *out, 84 long length, DES_key_schedule *ks1, 85 DES_key_schedule *ks2, DES_key_schedule *ks3, 86 DES_cblock *ivec, int *num); 87 88 DES_LONG DES_cbc_cksum(const unsigned char *input, DES_cblock *output, 89 long length, DES_key_schedule *schedule, 90 const_DES_cblock *ivec); 91 DES_LONG DES_quad_cksum(const unsigned char *input, DES_cblock output[], 92 long length, int out_count, DES_cblock *seed); 93 void DES_string_to_key(const char *str, DES_cblock *key); 94 void DES_string_to_2keys(const char *str, DES_cblock *key1, 95 DES_cblock *key2); 96 97 char *DES_fcrypt(const char *buf, const char *salt, char *ret); 98 char *DES_crypt(const char *buf, const char *salt); 99 100 int DES_enc_read(int fd, void *buf, int len, DES_key_schedule *sched, 101 DES_cblock *iv); 102 int DES_enc_write(int fd, const void *buf, int len, 103 DES_key_schedule *sched, DES_cblock *iv); 104 105=head1 DESCRIPTION 106 107This library contains a fast implementation of the DES encryption 108algorithm. 109 110There are two phases to the use of DES encryption. The first is the 111generation of a I<DES_key_schedule> from a key, the second is the 112actual encryption. A DES key is of type I<DES_cblock>. This type is 113consists of 8 bytes with odd parity. The least significant bit in 114each byte is the parity bit. The key schedule is an expanded form of 115the key; it is used to speed the encryption process. 116 117DES_random_key() generates a random key. The PRNG must be seeded 118prior to using this function (see L<rand(3)|rand(3)>). If the PRNG 119could not generate a secure key, 0 is returned. 120 121Before a DES key can be used, it must be converted into the 122architecture dependent I<DES_key_schedule> via the 123DES_set_key_checked() or DES_set_key_unchecked() function. 124 125DES_set_key_checked() will check that the key passed is of odd parity 126and is not a week or semi-weak key. If the parity is wrong, then -1 127is returned. If the key is a weak key, then -2 is returned. If an 128error is returned, the key schedule is not generated. 129 130DES_set_key() works like 131DES_set_key_checked() if the I<DES_check_key> flag is non-zero, 132otherwise like DES_set_key_unchecked(). These functions are available 133for compatibility; it is recommended to use a function that does not 134depend on a global variable. 135 136DES_set_odd_parity() sets the parity of the passed I<key> to odd. 137 138DES_is_weak_key() returns 1 if the passed key is a weak key, 0 if it 139is ok. 140 141The following routines mostly operate on an input and output stream of 142I<DES_cblock>s. 143 144DES_ecb_encrypt() is the basic DES encryption routine that encrypts or 145decrypts a single 8-byte I<DES_cblock> in I<electronic code book> 146(ECB) mode. It always transforms the input data, pointed to by 147I<input>, into the output data, pointed to by the I<output> argument. 148If the I<encrypt> argument is non-zero (DES_ENCRYPT), the I<input> 149(cleartext) is encrypted in to the I<output> (ciphertext) using the 150key_schedule specified by the I<schedule> argument, previously set via 151I<DES_set_key>. If I<encrypt> is zero (DES_DECRYPT), the I<input> (now 152ciphertext) is decrypted into the I<output> (now cleartext). Input 153and output may overlap. DES_ecb_encrypt() does not return a value. 154 155DES_ecb3_encrypt() encrypts/decrypts the I<input> block by using 156three-key Triple-DES encryption in ECB mode. This involves encrypting 157the input with I<ks1>, decrypting with the key schedule I<ks2>, and 158then encrypting with I<ks3>. This routine greatly reduces the chances 159of brute force breaking of DES and has the advantage of if I<ks1>, 160I<ks2> and I<ks3> are the same, it is equivalent to just encryption 161using ECB mode and I<ks1> as the key. 162 163The macro DES_ecb2_encrypt() is provided to perform two-key Triple-DES 164encryption by using I<ks1> for the final encryption. 165 166DES_ncbc_encrypt() encrypts/decrypts using the I<cipher-block-chaining> 167(CBC) mode of DES. If the I<encrypt> argument is non-zero, the 168routine cipher-block-chain encrypts the cleartext data pointed to by 169the I<input> argument into the ciphertext pointed to by the I<output> 170argument, using the key schedule provided by the I<schedule> argument, 171and initialization vector provided by the I<ivec> argument. If the 172I<length> argument is not an integral multiple of eight bytes, the 173last block is copied to a temporary area and zero filled. The output 174is always an integral multiple of eight bytes. 175 176DES_xcbc_encrypt() is RSA's DESX mode of DES. It uses I<inw> and 177I<outw> to 'whiten' the encryption. I<inw> and I<outw> are secret 178(unlike the iv) and are as such, part of the key. So the key is sort 179of 24 bytes. This is much better than CBC DES. 180 181DES_ede3_cbc_encrypt() implements outer triple CBC DES encryption with 182three keys. This means that each DES operation inside the CBC mode is 183an C<C=E(ks3,D(ks2,E(ks1,M)))>. This mode is used by SSL. 184 185The DES_ede2_cbc_encrypt() macro implements two-key Triple-DES by 186reusing I<ks1> for the final encryption. C<C=E(ks1,D(ks2,E(ks1,M)))>. 187This form of Triple-DES is used by the RSAREF library. 188 189DES_pcbc_encrypt() encrypt/decrypts using the propagating cipher block 190chaining mode used by Kerberos v4. Its parameters are the same as 191DES_ncbc_encrypt(). 192 193DES_cfb_encrypt() encrypt/decrypts using cipher feedback mode. This 194method takes an array of characters as input and outputs and array of 195characters. It does not require any padding to 8 character groups. 196Note: the I<ivec> variable is changed and the new changed value needs to 197be passed to the next call to this function. Since this function runs 198a complete DES ECB encryption per I<numbits>, this function is only 199suggested for use when sending small numbers of characters. 200 201DES_cfb64_encrypt() 202implements CFB mode of DES with 64bit feedback. Why is this 203useful you ask? Because this routine will allow you to encrypt an 204arbitrary number of bytes, no 8 byte padding. Each call to this 205routine will encrypt the input bytes to output and then update ivec 206and num. num contains 'how far' we are though ivec. If this does 207not make much sense, read more about cfb mode of DES :-). 208 209DES_ede3_cfb64_encrypt() and DES_ede2_cfb64_encrypt() is the same as 210DES_cfb64_encrypt() except that Triple-DES is used. 211 212DES_ofb_encrypt() encrypts using output feedback mode. This method 213takes an array of characters as input and outputs and array of 214characters. It does not require any padding to 8 character groups. 215Note: the I<ivec> variable is changed and the new changed value needs to 216be passed to the next call to this function. Since this function runs 217a complete DES ECB encryption per numbits, this function is only 218suggested for use when sending small numbers of characters. 219 220DES_ofb64_encrypt() is the same as DES_cfb64_encrypt() using Output 221Feed Back mode. 222 223DES_ede3_ofb64_encrypt() and DES_ede2_ofb64_encrypt() is the same as 224DES_ofb64_encrypt(), using Triple-DES. 225 226The following functions are included in the DES library for 227compatibility with the MIT Kerberos library. 228 229DES_cbc_cksum() produces an 8 byte checksum based on the input stream 230(via CBC encryption). The last 4 bytes of the checksum are returned 231and the complete 8 bytes are placed in I<output>. This function is 232used by Kerberos v4. Other applications should use 233L<EVP_DigestInit(3)|EVP_DigestInit(3)> etc. instead. 234 235DES_quad_cksum() is a Kerberos v4 function. It returns a 4 byte 236checksum from the input bytes. The algorithm can be iterated over the 237input, depending on I<out_count>, 1, 2, 3 or 4 times. If I<output> is 238non-NULL, the 8 bytes generated by each pass are written into 239I<output>. 240 241The following are DES-based transformations: 242 243DES_fcrypt() is a fast version of the Unix crypt(3) function. This 244version takes only a small amount of space relative to other fast 245crypt() implementations. This is different to the normal crypt in 246that the third parameter is the buffer that the return value is 247written into. It needs to be at least 14 bytes long. This function 248is thread safe, unlike the normal crypt. 249 250DES_crypt() is a faster replacement for the normal system crypt(). 251This function calls DES_fcrypt() with a static array passed as the 252third parameter. This emulates the normal non-thread safe semantics 253of crypt(3). 254 255DES_enc_write() writes I<len> bytes to file descriptor I<fd> from 256buffer I<buf>. The data is encrypted via I<pcbc_encrypt> (default) 257using I<sched> for the key and I<iv> as a starting vector. The actual 258data send down I<fd> consists of 4 bytes (in network byte order) 259containing the length of the following encrypted data. The encrypted 260data then follows, padded with random data out to a multiple of 8 261bytes. 262 263DES_enc_read() is used to read I<len> bytes from file descriptor 264I<fd> into buffer I<buf>. The data being read from I<fd> is assumed to 265have come from DES_enc_write() and is decrypted using I<sched> for 266the key schedule and I<iv> for the initial vector. 267 268B<Warning:> The data format used by DES_enc_write() and DES_enc_read() 269has a cryptographic weakness: When asked to write more than MAXWRITE 270bytes, DES_enc_write() will split the data into several chunks that 271are all encrypted using the same IV. So don't use these functions 272unless you are sure you know what you do (in which case you might not 273want to use them anyway). They cannot handle non-blocking sockets. 274DES_enc_read() uses an internal state and thus cannot be used on 275multiple files. 276 277I<DES_rw_mode> is used to specify the encryption mode to use with 278DES_enc_read() and DES_end_write(). If set to I<DES_PCBC_MODE> (the 279default), DES_pcbc_encrypt is used. If set to I<DES_CBC_MODE> 280DES_cbc_encrypt is used. 281 282=head1 NOTES 283 284Single-key DES is insecure due to its short key size. ECB mode is 285not suitable for most applications; see L<des_modes(7)|des_modes(7)>. 286 287The L<evp(3)|evp(3)> library provides higher-level encryption functions. 288 289=head1 BUGS 290 291DES_3cbc_encrypt() is flawed and must not be used in applications. 292 293DES_cbc_encrypt() does not modify B<ivec>; use DES_ncbc_encrypt() 294instead. 295 296DES_cfb_encrypt() and DES_ofb_encrypt() operates on input of 8 bits. 297What this means is that if you set numbits to 12, and length to 2, the 298first 12 bits will come from the 1st input byte and the low half of 299the second input byte. The second 12 bits will have the low 8 bits 300taken from the 3rd input byte and the top 4 bits taken from the 4th 301input byte. The same holds for output. This function has been 302implemented this way because most people will be using a multiple of 8 303and because once you get into pulling bytes input bytes apart things 304get ugly! 305 306DES_string_to_key() is available for backward compatibility with the 307MIT library. New applications should use a cryptographic hash function. 308The same applies for DES_string_to_2key(). 309 310=head1 CONFORMING TO 311 312ANSI X3.106 313 314The B<des> library was written to be source code compatible with 315the MIT Kerberos library. 316 317=head1 SEE ALSO 318 319crypt(3), L<des_modes(7)|des_modes(7)>, L<evp(3)|evp(3)>, L<rand(3)|rand(3)> 320 321=head1 HISTORY 322 323In OpenSSL 0.9.7, all des_ functions were renamed to DES_ to avoid 324clashes with older versions of libdes. Compatibility des_ functions 325are provided for a short while, as well as crypt(). 326Declarations for these are in <openssl/des_old.h>. There is no DES_ 327variant for des_random_seed(). 328This will happen to other functions 329as well if they are deemed redundant (des_random_seed() just calls 330RAND_seed() and is present for backward compatibility only), buggy or 331already scheduled for removal. 332 333des_cbc_cksum(), des_cbc_encrypt(), des_ecb_encrypt(), 334des_is_weak_key(), des_key_sched(), des_pcbc_encrypt(), 335des_quad_cksum(), des_random_key() and des_string_to_key() 336are available in the MIT Kerberos library; 337des_check_key_parity(), des_fixup_key_parity() and des_is_weak_key() 338are available in newer versions of that library. 339 340des_set_key_checked() and des_set_key_unchecked() were added in 341OpenSSL 0.9.5. 342 343des_generate_random_block(), des_init_random_number_generator(), 344des_new_random_key(), des_set_random_generator_seed() and 345des_set_sequence_number() and des_rand_data() are used in newer 346versions of Kerberos but are not implemented here. 347 348des_random_key() generated cryptographically weak random data in 349SSLeay and in OpenSSL prior version 0.9.5, as well as in the original 350MIT library. 351 352=head1 AUTHOR 353 354Eric Young (eay@cryptsoft.com). Modified for the OpenSSL project 355(http://www.openssl.org). 356 357=cut 358